The present application is a Continuation-In-Part of and claims priority of U.S. patent application Ser. No. 10/801,073, filed Mar. 15, 2004, which is a Continuation-In-Part of U.S. application Ser. No. 09/852,102, now U.S. Pat. No. 6,907,383, which is a Continuation-In-Part of U.S. application Ser. No. 09/257,896, filed Feb. 25, 1999, abandoned which is a Continuation-In-Part of U.S. application Ser. No. 08/623,569, now U.S. Pat. No. 6,017,143, application Ser. No. 09/852,102 is also a Continuation-In-Part of U.S. application Ser. No. 09/383,828, now U.S. Pat. No. 6,654,697, which is a Continuation-In-Part of U.S. application Ser. No. 09/257,896, filed Feb. 25, 1999 which is a Continuation-In-Part of U.S. application Ser. No. 08/623,569, filed Mar. 28, 1996, now U.S. Pat. No. 6,017,143, the content of which is hereby incorporated by reference in its entirety.
The present invention relates to process control systems of the type used to monitor and/or control operation of industrial processes. More specifically, the present invention relates to diagnostics of such process control systems.
Field devices (devices such as process controllers, monitors and transmitters) are used in the process control industry to remotely control or sense a process variable. For example, a process variable may be transmitted to a control room by a transmitter for use in controlling the process or for providing information about process operation to a controller. For example, information related to pressure of process fluid may be transmitted to a control room and used to control the process, such as oil refining.
When a device used in industrial process fails, it is often necessary to shut down the entire process so that the failed device can be repaired or replaced. Typically, it is difficult to predict an impending failure of a process device prior to its occurrence. Thus, when the process device does fail, it occurs unexpectedly or with very little warning, and may require the unexpected shut down of the entire process. Although various attempts have been made at detecting and/or predicting a failure or impending failure, there is an ongoing need for such diagnostic techniques. Prior prediction of a pending failure allows the failing device to be replaced as desired prior to its ultimate failure.